I think that for the most part, -at least initially, -it would be effecting only the Sunward Facing side of the Earth, -at impact time. But depending on the Duration of the Flare Hit, -some of Earth's Night Side will rotate into the Damage. Also, Satellites above, will have far less "earth Shadow Effect", -than things down here on the ground. Also, and increasingly over time, --there should be some "Wind and Ocean Current Spreading Effects", as well.